An implant that has become known as an example is essentially a metal band, on which lateral straps are arranged, and both the metal band and the straps have screw holes, which are provided for accommodating bone screws. These metal bands are available in different lengths to ensure that they can be selected corresponding to the physical conditions of a given patient.
The vertebrae are fixed with such band-like implants by screwing the implant onto a vertebra, after a so-called bed for the implant has been created on the surface of the vertebra by, e.g., milling off the vertebral bone W in order to prepare a corresponding support surface for the band-like implant. A bed also must be formed on the adjacent vertebra to be fixed in order to subsequently screw this vertebra together with the band-like implant in the medically necessary position of the vertebra.
The disadvantage of such a band-like implant is that these procedures are to be performed under surgical conditions and they also require removal of the bone chips and the like, generated during the preparation of the two beds for the band-like implants. Moreover, the heads of the bone screws usually project from the vertebra together with the band-like implant, which leads to unpleasant, symptom-producing accompanying phenomena, especially in the area of the esophagus. In addition, it may be necessary, depending on the location of the vertebrae or their damage, to provide a washer between the band-like implant and one vertebra or both vertebrae in order to achieve a medically suitable fixation. In particular, the site at which the bone screws are screwed in cannot be selected solely based on medical criteria, because the screw holes in the band-like implant are permanently predetermined, as a result of which fixation cannot be always performed in a medically optimal manner. This may lead to a limitation of the medically necessary measures, especially in the case of osteoporosis, because the location of the screw holes must be selected in this case so as to ensure that they will not break out. There also is a risk of breaking out especially in the case of screw holes in peripheral zones of the vertebra, which frequently must be used in the case of the band-like implant, because precisely the screw holes are permanently predetermined by their distances on the band-like implant. Moreover, it is necessary to keep in stock the different, medically necessary sizes of band-like implant.